Bacteria Bacteria are pro karyotes “first seed” (single cells that do not contain a nucleus, or membrane bound organelles). Bacteria are microscopic and can only be seen through a microscope There are 2 Domains of bacteria, Eubacteria and Archaea

Eubacteria “true bacteria” Typical “monerans” found where humans live Evolution of the 3 Domains                         

Archaea “archaic/old” extremophiles Methanogens Thermophiles Acidophiles Halophiles Alkaliphiles Psychrophiles Xerophiles Barophiles Archae vs Bacteria

Bacteria Characteristics Bacteria are distinguished from other living things because of their cell structure: All bacterial cells have a cell wall surrounding a cell membrane, inside of which lies the unbound nuclear matter and other material.

Bacteria have extra genomic DNA that is round and called a “plasmid” Plasmid Cloning

Bacteria Classification There are three types of bacterial cells, based on shape: spherical (coccus), rodlike (bacillus), and spiral (spirillum).

Coccus

Bacillus

Spirilla

Some bacteria have flagella for locomotion and some have pili to transfer DNA (conjugation) and to stick to substrates of host cells Bacterial Chemotaxis

Gram Staining The Gram stain is named after the 19th century Danish bacteriologist who developed it. The bacterial cells are first stained with crystal violet. then treated with alcohol or acetone, whichwashes the stain out of gram-negative cells and then counterstained. Bacteria that are not decolorized by the alcohol/acetone wash are gram-positive. Gram Stain Animation

Gram + Stains purple Cell wall 90% peptidoglycan

Gram - Stains red Multi-layered cell wall with inner and outer membranes and an intermembrane space

Harmful Bacteria A number of bacteria cause disease, these are called pathogenic bacteria. They can cause diseases of plants, animals, fungi, protists and other bacteria E. coli infection Salmonella infection

Some bacterial diseases include: strep throat, scarlet fever, toxic shock syndrome, pneumonia, ear infections, gonorrhea, syphilis, Tuberculosis Bacteria can also be used by some countries to harm other countries in an act called bioterrorism Eczema w/ 2o infection

Helpful Bacteria actinomycetes, produce antibiotics such as streptomycin and nocardicin live symbiotically in the guts of animals Bacteria put the tang in yogurt and the sour in sourdough bread roots of certain plants, converting nitrogen into a usable form.

break down dead organic matter of such immense importance because of their extreme flexibility, capacity for rapid growth and reproduction, and great age - the oldest fossils known, nearly 3.5 billion years old used in genetic engineering Bioremediation

Producers in Geothermal Vents

Reproduction Bacteria reproduce asexually by binary fission Bacterial Conjugation (lateral/horizontal gene exchange) Bacterial Transformation (lateral/horizontal gene exchange) Bacteria life cycle

Response to the Environment Intracellular signaling not only brings bacteria together in biofilms (through Quorum sensing A process by which a bacterium detects the density of other bacteria in an area), it also regulates the coordinated delivery of high doses of these antibiotics from the denser bacterial population. Biofilm Life Cycle

Bacterial Links Bioterrorism: Bacterial Cell Walls: 10 Ways a World Will End: Monster Plague Discovery of the Germ Theory Antibiotics Tutorial Anti-antibiotics/Efflux Pump Immunology Primer When Worlds Collide, Macro vs. Micro Immuno- biology Animations